Valve seal apparatus

ABSTRACT

A valve or regulator apparatus for fluid flow, in which a pressure differential shifts the valve to different positions, one portion of the valve being subject to low pressure, such as pressure in an atmospheric chamber, and the other portion of the valve being subject to relatively high pressures. A valve stem, or the like, is exposed to the atmospheric pressure in the chamber and makes a sealing fit in a guide. A seal chamber is provided containing a liquid, such as silicone oil, which is prevented from entering the atmospheric chamber by the seal between the valve stem and the guide, the silicone oil preventing the fluids under pressure, which flow through the valve, from contacting and acting upon the seal adjacent the atmospheric chamber.

United States Patent [72] inventor David V. Chenoweth 2,761,465 9/1956Garrett 137/ 155 Houston, Tex. 2,894,793 7/1959 Robinson 277/135 [2]]Appl. No. 757,688 2,908,290 10/1959 Hamilton-Peters 251/57 [22] FiledSept. 5 1968 Divisioh ofSer. No. 653,372, Pat. No. f' g 'i' Q jl 'f3,474,859. :sszstant gamme; 1 1pm rig t 45 Patented 1111.9, 1971 [73]Assignee Baker Oil Tools, Inc.

City of Commerce, Calif. a corporation ofcahforma ABSTRACT: A valve orregulator apparatus for fluid flow, in which a pressure differentialshifts the valve to different posi- [54] VALVE SEAL APPARATUS tions, oneportion of the valve being subject to low pressure, sclaims (DrawingFigs uch as pressure in an atmospheric chamber, and the other portion ofthe valve being subject to relatively high pressures. U-S- A alve tem orthe like is exposed to the atmospheric pres- F16! 39/02 sure in thechamber and makes a sealing fit in a guide. A seal [50] Field otSearch137/542, chamber is provided containing a liquid Such as silicone oil,155; 251/57; 1 16/ 1 15, 224; 277/(lnqu1re 135 which is prevented fromentering the atmospheric chamber by f d the seal between the valve stemand the guide, the silicone oil [56] Re erences preventing the fluidsunder pressure, which flow through the UNITED STATES PATENTS valve, fromcontacting and acting upon the seal adjacent the 2,685,886 8/1954 Peters137/155 atmospheric chamber.

we, ,2 ZIQb-Q K j g f yw 210a:- I, 7 200a l, 2l4a 1H4 j ql Y '4 \1 A iI? 1 VALVE SEAL APPARATUS This application is a division of myapplication for Well Flow Control Apparatus, Ser. No. 653,372, now U.S.Pat. No. 3,474,859 filed Jul. 14, 1967.

The present invention relates to valve or flow regulator apparatus, andmore particularly to seal devices for preventing undesired gas andliquid leakage past certain portions of the apparatus.

Valve or flow regulator apparatus are known in which it is desirable toprevent fluids from moving past the apparatus into a lowpressurechamber, such as a closed atmospheric chamber. Heretofore,reliance has been placed upon mechanical seals for preventing such flowof liquids and gases into the atmospheric or corresponding chamber.However, it has been found that gas leaks through seal imperfections,both metallic and elastomeric, into the chamber, thereby causing anincrease in the pressure in the chamber and inappropriate operation ofthe valve apparatus, if not eventually causing its failure to operate atall. Atmospheric chambers have been scaled heretofore through the use ofbellows. However, such bellows cannot stand the high pressuredifferentials, such as are encountered in subsurface oil well tools.

By virtue of the present invention, the aforenoted difficulties areovercome. A valve or flow regulator apparatus is provided in which gasand other fluid are prevented from leaking into an atmospheric or otherlow pressure chambers. A

separate seal chamber is provided in which a liquid is confined thatwill prevent the gas or other fluid from migrating to the atmosphericchamber. This liquid is retained in its seal chamber by suitable sealrings, for example, of the elastomer type, these seal rings beingeffective in preventing leakage of liquids thereby, but sometimespermitting leakage of .gas thereby. The liquid seal, such as siliconeoil, has very little capacity for absorbing gas, but will still preventgas from moving through it. Thus, the silicone or other will stillprevent gas from moving to the region of the elastomer seal, while theelastomer seal will prevent silicone oil or other liquid from movingpast it into the atmospheric chamber. Accordingly,

the combination of the elastomer seal and the body of sealing liquid,such as silicone oil, effectively prevent passage of all liquids andgases into the atmospheric chamber. A sliding seal can be providedbetween the vale or regulator body and a valve stem, or the like, thatprojects into or is exposed to the pressure in the atmospheric chamber,permitting the valve or regulator parts to have a large range ofmovement. Despite the imposition of comparatively high pressures on themovable valve parts, gas and liquid migration past the combination ofsilicone oil seal and elastomer seal is precluded.

This invention possesses many other advantages, and has other purposeswhich may be made. more clearly apparent from a consideration of a formin which it may be embodied. This form is shown in the drawingsaccompanying and forming part of the present specification. It will nowbe described in detail, for the purpose of illustrating the generalprinciples of the invention; but it is to be understood that suchdetailed description is not to be taken in' a limiting sense, since thescope of the invention is best defined by the appended claims.

Referring to the drawings:

FIG. 1 is a diagrammatic view illustrating an apparatus disposed in awell bore, and embodying one or more flow regulator mechanisms thatincorporate the invention therein;

FIGS. 2a, 2b and 2c constitute a longitudinal section through a flowregulator mechanism for controlling the rate of flow from one of theproduction zones disclosed in FIG. 1 into a tubing string, FIGS. 2b and2c constituting lower extensions of FlGS. 2a and 2b, respectively.

Referring to FIG. 1, the present invention is illustrated in connectionwith a concentric. tubing-casing installation, wherein the tubing T isconcentrically disposed within the casing C and extends through the wellzones Z1 and Z2, the easing also being perforated at P1 and P2 to allowwell production fluid to flow from the zone Z1 into the annular spacebetween the tubing and casing and between the well packers 1 and 2;while production fluid from zone Z2 will flow through the perforationsP2 into the casing C below the well packer 2. these packers, as is wellknown, forming a seal with the tubing T and isolating the zones from oneanother.

The fluid will pass into mass flow control apparatus M in the respectiveisolated'regions of the casing through inlet ports 30, and, in a mannerwhich will now be described, such fluid will pass upwardly into thetubing string T, the fluid from the respective zones being comingled inthe tubing.

FIGS. 2a to 2c show in detail a representative mass flow apparatus inthe concentric tubing-casing installation, such as that generallyillustrated in FIG. 1. As seen in F105. 2to 2c, the assembly comprises ahousing composed of an elongate body 31 having an upper sub 32threadedly connected to the tubing T at its upper end. At the lower endof the body 31 is a bottom sub 33. connected to a downward extension ofthe production tubing T, and which will be understood to extenddownwardly through the packer 2 shown in FIG. 1 for connection to asimilar assembly for controlling the production from the lower zone Z2.

lnteriorly of the housing 31 isa fixedl sleeve 34 secured in spacedrelation to the housing by a plurality of nipples 35 providing the fluidinlets 30 from the well casing, these nipples being welded, or otherwisesecured, to the housing 31 and to the sleeve 34. if desired, a sleevevalve 36 may be provided for selectively opening and closing the ports30, this sleeve valve being reciprocably disposed within the fixedsleeve 34 and having valve ports 37 adapted, when the sleeve valve 36 isin a lower position, to register with the ports 30 in nipples 35. Thesleeve 36 has an upper set of ports 37a adapted to be disposed above thethe upper end of the fixed sleeve 34 when the sleeve 36 is in said upperposition. This sleeve valve structure is optional, forms no part of thepresent invention, and is more particularly'shown and described inapplication Ser. No. 488,943,

filed Sept. 21, 1965, now U.S. Pat. No. 3,371,717, granted Mar. 5, 1968.In the illustrative embodiment, however, the sleeve valve forms a partof the running and recovery assembly, including a recovery head having abody 38 adapted to be engaged by a suitable wireline running andrecovery tool, as more particularly disclosed in the aforementionedapplication. The recovery head body 38.has lateral ports 38acommunicating with ports 37a in the valve sleeve 36 when the latter isin the lower position, as shown in F i6. 20. These ports 38a lead intoan axially extended passage 38b in the head which opens into theproduction tubing or conduit T. The running and recovery head alsoincludes suitable latch mechanism 380 for holding the assembly,including the mass flow apparatus M hereinafter described, within thehousing 31.

Vale sleeve 36 is adapted to be shifted by latch elements 36a to itslower position with the ports 38a communicating with the inlets 30, andwhen the valve is moved to an upper position, springlike latch elements3612 are adapted to engage in an enlarged bore or groove 32b in theupper sub 32 to hold the valve sleeve 36 in an upper position (notshown) at which the inlets 30 will be closed.

Also included in the recovery head is a lower body portion 39 whichsupports, by a threaded connection 39a, the body 211 of the upstreampressure regulator. This body includes an upper section threadedlyconnected to the body of the running and recovery head and extendeddownwardly in sealed relation to the valve sleeve 36, there beingsealing means or packings 40, 41 211 and in sealing engagement with theinside of the valve sleeve 36. Between these packings 40, 41, the body211 of the upstream pressure regulator is provided with the inlet ports218. The body section 211 is threadedly connected at 211a to adownwardly extended section 211b, to the lower end of which a coupling2l1c is threadedly connected. in the coupling 2110 is a backflowpreventing ball valve 220 engageable with a seat 220a held in place by aring 2220b which engages the lower end of the body section 211.

It will be noted that the body sections 211 and 211b, together with thecoupling 211e, constitute an axially extended portion of the pressureregulator body 210, to which the coupling 2116 is threadedly connected,as seen in FIG. 2b. At the lower end of the body 210 is an end piece210a threadedly connected and sealed in relation to the body 210 at210b, as shown in FIGS. 2c, the end piece having a chamber 214 thereinprovided in an end cap 214a which is suitably welded to, or otherwiseformed as, a part of the end piece 210a.

Reciprocably disposed within the body 210 is a stem 212 having thereonadjustable nuts 217 forming an upper abutment for a coil spring 216. Atits lower end, as seen in FIG. 2c, the stem 212 extends in sealedrelation into the chamber 214 and is limited in respect of its upwardmovement by a snap ring 212a mounted thereon and engageable with thelower end of a guide 212b to which the end piece 210a is attached, thestem 212 extending through the guide into the chamber 230 within thebody 210. It will be noted that the stem 212, as seen in FIG. 2c,extends through a chamber 200 which contains a quantity of lubricant,such as silicone oil, whereby the stem section extending through thebody sections 212b, 210a will be lubricated to reduce friction effects.The lubricant is confined by suitable sealing means at 2000 between thestem and body, and by the sealing means 200b which seals the lower endof the stem 212 in the atmospheric chamber 214.

The upper extremity of the stern 212 is provided with a th'ottle valvemember 215 which is slidably disposed within a valve guide 215a, thelatter having inlet ports 221 leading to a bore 221a through the guide215a. The throttle valve member 215 has a reduced section 2151; which,when the valve is in the open position, as shown in FIG. 2b, permitscontrolled flow through the passage 221a of the vale guide 215a.

The throttle valve end 215 of the stem 212 will assume a position atwhich flow through inlet 221, 221a is controlled as a function of thepressure acting on the cross-sectional area of the valve member 215 toprovide a force counteracted by the force of the spring 216, theremainder of the stem being pressure balanced.

In the illustrative embodiment of FIGS. 2a to 2c, assuming the ports and37 to be open, as shown in FIG. 2a, production fluid from the well zonein. which the apparatus is disposed may pass through these ports andflow downwardly through a central passageway 2211) in the regulator bodysection 211 past the check valve 220. The fluid will then proceeddownwardly through the inlet ports 221 in the valve guide 215a, andthrough passage 221a into the chamber 230, from whence it may flowthrough ports 208 into the annular space defined between the housing 31and the flow regulating apparatus M, as shown in FIG. 2b. Then, as shownin FIG. 2a the fluid will continue to pass upwardly through the ports37a in the valve sleeve 36 and through the ports 38a in the recoveryhead body 38 so as to flow upwardly through the passage 38b in thelatter. The rate at which the production fluid may flow through thethrottle valve guide 215a will be determined by the force supplied byspring 216 tending to close off the flow and acting against the forceprovided by the pressure of the production fluid acting on thecross-sectional area of the throttle valve member 215, so that therewill be maintained a constant back pressure on the formation and,therefore, a constant mass rate of production fluid flow into the tubingT. The constant pressure on the formation will be maintainednotwithstanding the use of auxiliary lift equipment in the tubing Tabove the mass rate flow control means, such as gas lift apparatus orthe usual pumping apparatus, all well known in the art.

As noted above, a lubricant, such as silicone oil, is disposed in theseal chamber 200, which will have the effect of reducing frictioneffects to enable the free sliding of the stem 212 within the body 210of the pressure regulator. The body of silicone oil also serves theimportant purpose of protecting the atmospheric chamber 214. The O-ringseal members, such as seal rings 200a and 200b, will prevent leakagethereby of a viscous liquid, but such O-rings are permeable to gas.Thus,

the O-rings 200b will prevent the silicone oil in the chamber 200 fromflowing downwardly into the atmospheric chamber 214, but, by themselves,they are permeable to gas and might, if used alone, permit gas in thewell bore from leaking downwardly past the seal rings 200b and into theatmospheric chamber 214. Such leakage of as will allow pressure to buildup in the atmospheric chamber 214, and could render the pressureregulator apparatus inoperable to function with the desired degree ofeffectiveness.

The silicone oil in the seal chamber 200 acts as a seal to prevent anygas that might leak past the seal rings 200a from passing along thelower portion of the stem beyond the seal rings 200b and into thechamber 214. Silicone oil has a low gas solubility and, in addition,will retain its viscosity at a desirable value, since its viscositychanges only a small degree with rather large temperature changes. Thesilicone oil, in combination with the seal rings,- acts an an effectivebarrier, preventing gas migration into the atmospheric chamber 214. Theseal rings 200b are effective to prevent migration of the silicone intothe chamber 214, and the silicone body in the chamber 200 preventsmigration of gas thereby and to the region of the seal rings 200b.

It has been found that, in the absence of the lubricant seal in thechamber 200, gas will pass through seal rings and past the metallicsurfaces between the stem- 212 into the atmospheric chamber 214. Theprovision of the liquid barrier in the chamber 200 is found to preventgas leakage into the chamber 214. Thus, through the provision of theliquid barrier, applicant provides an apparatus that can functioneffectively under very high pressure differentials between the pressureacting on the valve stem 212 and the relatively small pressure in theatmospheric chamber 214. The use of bellows has been proposed heretoforethis purpose, but such bellows cannot withstand very high differentialpressures of the order required in subsurface tools, and particularlywhere a substantial range of movement of the valve or regulator portionsof the mechanism is required.

lclaim:

1. ln flow control apparatus: body means having an inlet passage, anoutlet passage, and a low pressure chamber; valve means in said bodymeans for controlling fluid flow between said passages, said valve meansincluding a fluid pressure responsive member shiftable in said bodymeans and having a first surface exposed to the pressure in said lowpressure chamber and a second surface exposed to the fluid pressure inone of said passages; said body means having a seal chamber throughwhich said fluid pressure responsive means extends; means providing aslidable elastomer seal between said member and body means at one sideof said seal chamber between said chambers; means providing a slidableelastomer seal between said member and body means at the opposite sideof said seal chamber; a liquid in said seal chamber surrounding andcontacting said member and contactable with said slidable elastomerseals, said liquid having low gas solubility; said first surface beingon one side of said seal chamber and elastomer seals and said secondsurface being on the opposite side of said seal chamber and elastomerseals; said low pressure chamber containing a gaseous medium atsubstantially atmospheric pressure.

2. In flow control apparatus as defined in claim 1; wherein said liquidis a lubricant having small viscosity change characteristics whensubjected to large temperature changes.

3. In flow control apparatus as defined in claim 1, wherein said liquidis a silicone oil.

1. In flow control apparatus: body means having an inlet passage, anoutlet passage, and a low pressure chamber; valve means in said bodymeans for controlling fluid flow between said passages, said valve meansincluding a fluid pressure responsive member shiftable in said bodymeans and having a first surface exposed to the pressure in said lowpressure chamber and a second surface exposed to the fluid pressure inone of said passages; said body means having a seal chamber throughwhich said fluid pressure responsive means extends; means providing aslidable elastomer seal between said member and body means at one sideof said seal chamber between said chambers; means providing a slidableelastomer seal between said member and body means at the opposite sideof said seal chamber; a liquid in said seal chamber surrounding andcontacting said member and contactable with said slidable elastomerseals, said liquid having low gas solubility; said first surface beingon one side of said seal chamber and elastomer seals and said secondsurface being on the opposite side of said seal chamber and elastomerseals; said low pressure chamber containing a gaseous medium atsubstantially atmospheric pressure.
 2. In flow control apparatus asdefined in claim 1; wherein said liquid is a lubricant having smallviscosity change characteristics when subjected to large temperaturechanges.
 3. In flow control apparatus as defined in claim 1, whereinsaid liquid is a silicone oil.